Answer:
![\boxed{\sf{D. \quad 10a+5b}}](https://img.qammunity.org/2023/formulas/mathematics/high-school/akzz80ls2ms8bnp9ylsj5s6ttilqztzjpn.png)
Explanation:
Use a distributive property.
Distributive property:
![\Longrightarrow: \sf{A(B+C)=AB+AC}](https://img.qammunity.org/2023/formulas/mathematics/high-school/ehnkapp48ta8gokwebqg42yxoaybxkvydc.png)
⇒ 5(a+a+b)
⇒ a+a=2a
Rewrite the problem down.
![\Longrightarrow: \sf{5(2a+b)}](https://img.qammunity.org/2023/formulas/mathematics/high-school/3fegfrtogz5lxadl345qbwd7jwwuqouq55.png)
Multiply should be expanded.
⇒ 5*2a=10a
⇒ 5*b=5b
Rewrite the problem.
⇒ = 10a+5b
- Therefore, the final answer is 10a+5b.
I hope this helps you! Let me know if my answer is wrong or not.